In recent years, higher integration and miniaturization of semiconductors widely used in electronic equipment, communication instruments, personal computers, and the like have accelerated increasingly. With this, various characteristics required for laminates for semiconductor packages used in printed circuit boards have become increasingly strict. Examples of the required characteristics include characteristics such as low water absorbency, moisture absorption heat resistance, flame retardancy, a low dielectric constant, a low dielectric loss tangent, a low thermal expansion coefficient, heat resistance, chemical resistance, and high plating peel strength. But, these required characteristics have not always been satisfied so far.
Conventionally, as materials for printed circuit boards having excellent heat resistance and electrical characteristics, cyanate compounds are known, and in recent years, resin compositions using cyanate compounds in combination with epoxy resins, bismaleimide compounds, and the like have been widely used for materials for highly functional printed circuit boards such as for semiconductor plastic packages, and the like.
For example, in Patent Literatures 1 and 2, resin compositions, which contains a cyanate compound and an epoxy resin that have excellent characteristics such as adhesiveness, low water absorbency, moisture absorption heat resistance, and insulation reliability, are proposed.